Viscometer



Feb. 16, 1965 w. a. BROOKFlELD 3,169,392

VISCOMETER Original Filed April 2 1960 '7 Sheets-Sheet 1 Feb. 16, 1965w. B. BROOKFIELD 3,169,392

VISCOMETER Original Filed April 26, 1960 7 Sheets-Sheet 2 a: I E I 1965w. a. BROOKFIELD 3,159,392

VISCOMETER Original Filed April 26. 1960 7 Sheets-Sheet s Feb. '16, 1965w. a BROOKFIELD 3,159,392

JISCOMETER Original Filed April 26, 1960 7 Sheets-Sheet 4 1965 w. B.BROOKFIELD VISCOMETER Original Filed April 26. 1960 7 Sheets-Sheet 5Feb. 16, 1955 w. B. BROOKFIELD VISCOMETER 7 Sheets-Sheet 6 OriginalFiled April 26, 1960 Qhi mhi v w wmmw c sw Feb. 16, 1965 w. B.BROOKFIELD VISCOMETER 7 Sheets-Sheet 7 Original Filed April 26, 19603,169,392 WSCGMETER William B. Broohfield, 9 Usage Road, Canton, Mass.Continuation of appiication Ser. No. 24,814, Apr. 25, B69. Thisapplication Dec, 17, 1952, See. No. 245,637 19 ((33. 7359) The presentinvention relates to viscometers and particularly to viscometers whereinthe operation of the control means is effected by pneumatic signalsgenerated in response to accurately detected viscosity changes of asmall order. The present application is a continuation of myapplication, Serial No. 24,814, filed April 26, 1966, and now abandoned.

There are many instances where not only is the detection of viscositychanges but also the immediate correction thereof is highly important.Examples of such instances are to be found in the graphic arts where thequality of the worlr is adversely affected if the viscosity of the inkdeparts from a predeter Lined value. The term ink, as used herein, meansnot only gravure and aniline inks but also varnishes and lacquers usedin the graphic arts. it will be appreciated that the relation betweensolvent concentration and viscosity is such that small variations in theformer are attended by large variations in the latter and that thehigher the press speed the faster drying must be the solvents thusmaking the problems even more acute.

The principal objective of the present invention is to provide a viscoactor that is capable of accurately sensing and effecting the correctionof small viscosity changes efiiciently, accurately, and reliably withoutthe use of complex and delicate circuitry.

In accordance with the invention, this objective is attained byproviding a viscometer having a motor driven flywheel provided with amember which has an outlet port to which air under pr ssure is deliveredwhile the flywheel is rotating. A valve mem er for the outlet port ismounted to move into and out of a port closing position and is attachedto a coil spring which constitutes the driving connection with a drivenshaft and which is arranged and disposed for rotating the latter and tobe partly wound, when the driven shaft torque exceeds a predeterminedvalue, thus to swing the valve member out of its port closing positionthereby to provide the basis for a pulse generation. A connectionbetween the fiywheel and the driven shaft becomes operative when thecoil spring connection has become wound to a predetermined extent.

A viscometer, in accordance with the invention, is adjustable to.respond to small increases in viscosity of the material and topneumatically affect a controller so as to cause, through simple andreliable means, the operation of a valve thus to admit solvent until theviscometer senses that the desired small decrease in viscosity has beenmade to effect the needed correction of the system.

To carry out the above objectives, pressure operated means are providedto operate a control switch in a circuit, preferably intermittently oened, to a solenoid operated valve in the solvent supply line. Thesesame means are also employed to actuate limit switches in circuitsoperable to actuate signals that indicate system failures whether on thehigh viscosity side, as when the solvent supply fails, or on the lowviscosity side, as when the ink supply fails or an excess of solvent ispresent.

As the pressure variations attendant the operation of the viscometer areinherently small, the invention provides means whereby these smallpressure changes are operative to control the pressure operated meansaccurately in response thereto on a basis that permits substantialpressures to be employed in the latter to ensure atssasz Patented Feb.16, 1965 positive actuation of the control and limit switches by simpleand rugged mechanisms.

In the accompanying drawings, there is shown an illustrative embodimentof the invention from which these and other of its objectives, novelfeatures, and advantages will be readily apparent.

In the drawings:

FIGURE 1 is a side elevation of a viscometer in accordance with theinvention with its housing shown in section;

FIGURE 2 is a similar view showing the viscometer as turned from itsFIGURE 1 position;

FIGURE 3 is a section taken approximately along the indicated lines 33of FIGURE 1;

FIGURE 4 is a section taken approximately along the indicated lines 4-4of FIGURE 2;

FiGURE 5 is a bottom view of the flywheel;

FIGURE 6 is a section, on an increased scale, taken approximately alongthe indicated lines 6-6 of FIG- URE 3;

FIGURE 7 is a section taken approximately along the indicated lines 7--7of FIGURE 1;

FIGURE 8 is a partly sectioned side View, on an in creased scale, of auniversal joint in the driven shaft;

FIGURE 9 is a side elevation of the joint showing it as turned 90 fromits FIGURE 8 position;

FIGURE 10 is :a perspective view of the flapper valve and coil springconnection with the driven shaft;

FIGURE 11 is a somewhat schematic view of a viscometer and thepneumatically actuated controller;

FIGURE 12 is a schematic illustration of a typical installation inaccordance with the invention, and

FIGURE 13 is a view illustrating a typical electric circuit.

In the drawings, a viscometer, in accordance with the invention, isgenerally indicated at 26 and shown as having a base 21 to which theflange 22 of a housing 23 is clamped, as by screws 2 against an annularseal 25. The base 21 consists of upper and lower plates 26 and 27 lockedtogether by units 23 establishing sockets for the screws 24.

A support 29 of arcuate section is attached as at 39 to the base 21 andincludes vertically spaced, transversely disposed shelves 31 and 32. Theshelf 31 is supported by a tubular post 33 and is anchored thereto by ascrew 34 which extends through the post 33 and into the base 21.

A generally indicated motor 35 has flanges 36 supported by spacers 37and anchored by screws 38 which extend through the spacer 37 and intothe shelf 31. Exteriorly of the housing 23, the base has a pair ofthreaded ports 39 and 4t? both of which are in communication with theport 41 in the base Within the housing 23 (see FIG- URES 4 and 7),through a channel 42 in one of the proximate faces of the baseestablishing plates. An electric cable 43 extends through the port 39and is anchored by the clamp 4- threaded on the port 39.- The cableleads 43 43 and 43 extend upwardly through the port 41 around thesupport 29 and upwardly to the motor 35.

The drive shaft 45 of the motor 35 is provided with a gear 46 meshingwith the larger gear 47 of the idler 4-8 mounted on the spindle 49attached to the shelf 31. The smaller gear 50 of the idler meshes with agear 51 fast on a hollow shaft 52 journalled in and extending throughthe hub 53 with which the shelf 31 is provided. At its lower end, theshaft 52 has a radially disposed arm 54 having a radial passage 55 incommunication with the passage defined by the hollow shaft 52. A conduit56 for air under pressure is attached to the port 39 by the threadedfitting 57 and a conduit 58 extends therefrom upwardly through the port41 and is anchored to an edge of the support 29 as by clips 59. At itsfree end, and as may best be seen in FIGURE 6, the conduit 58 has adownwardly disposed nozzle provided with an antiblock and into contactwith the portion 63.

A flywheel 68 has, as may be seen in FIGURE 6, axial pivots 69 and 70and diametrically arranged holes 71 through one of which freely extendsa spacer 72 connecting the arm 54 to a radial arm 73 anddefining aU-shaped connector. The arms 54 and 73 have seats for the flywheelpivots 69 and 70 which extend downwardly through the arm 73. The spacer72 has a blade member 74 centrally entered between appropriate turns ofa coiled spring 75 connected as a chord to the flywheel 68 thus toprovide a yieldable, resilient connection therebetween and the driveshaft 52.

A second U-shaped connector 76 has upper and lower parallel arms 77 and78 supported by the flywheel pivots I 69 and 70, respectively, forrotation independently thereof. The arm 77 includes a radially disposedextension 79 provided with a flat head 80movable into and out of aposition in which it functions as a flapper valve to close the port 81ofan outlet member 82 to which one end of a flexible conduit 83 isconnected. The other end of. the conduit 83 is connected to the rigid,curved tubing 84 secured in the radial passage 55. The outlet member 82includes a bottom part 85 (see FIGURE 5) slidably guided in a slot 86 inthe flywheelS and has a screw 87 threaded therethrough. The screw 87 isheld in place by the arms 88 of a clip 39 (see FIGURE 4), attached tothe upper face of the flywheel 68 as. by screws 90. A set screw 91 isprovided to lock the outlet mem ber 82 in position.

shaft 94. The shaft 94 has a hub 95 to which the inner. 1

end of a spiral spring 96 is anchored. The outer end of the spring 96 isattached to the downturned lug'97 at the outer end of the lower arm 78of the connector 76 which end is diametrically opposed to the flapperValve'head 30. The spring 96 is the driving connection between theflywheel 68 and the driven shaft 94 and, if a predetermined torque isexceeded, the spring 96 becomes partly wound and swings the flappervalve 80 into an open position. In order to adjust the effect of thecoil spring 96 and, as may be seen in FIGURE 5, the lower arm 78 of theconnector 76 has an extension 98 to which one end of a tensioning spring99 is anchored. The other end of the spring 99' is anchored to theshort, arm of a bell crank lever 100 pivoted as at 101 to the flywheel68 and frictionally engaging therewith to maintain itself in anyadjusted position. I

The hollow shaft 93 is provided, at its upper end, see FIGURE 6, with aradial arm, 102 to whose outer end there is connected the downturned endof the arm 103 extending radially outwardly from the arm 73 to which itis attached. At'its lower end, the hollow shaft 93 has an arm 104clamped thereto and which has, at its outer end, a downwardly disposedspacer 105 provided with an arm 106 extending radially inwardly with aresilient support 107 at its free end for the upwardly disposedbearing108 for the pivot 109 at the lower end of the shaft 93. The pivot 70extends into an axial socket 94 in the upper end of the shaft 94.

The shaft 94 has a radial arm 110 having a spacer 111 at its outer endsupporting a lower arm 112 extending radially inwardly below the arm 106but is itself disposed to 'be engaged by the arm 106 on rotation of oneshaft relative to the other to a predetermined extent. The. arm

112 has a-recess 113, see FIGURES 6, 8, and 9, in'its lower face toreceive the ring 114 which is provided with' radially alined grooves 115to receive the ends of the pivot Y 116 having pivots 117 disposed atright angles to its axis and connected to the fork 118 of the shaft 119.The ring 114 is resiliently retained in place by the leaf spring 129.

The shaft 119 extends freely through a sleeve 121 threaded into theplate 27 of the base 21 and is locked thereto by a lock nut 122. Acollar 123 is clamped to the exposed end of the shaft 119 which includesan eye 124. A spindle 125 of the desired length is connected through theeye 124 and has a member such, for example, as the member 126 which, asit rotates, is subject to the drag of the liquid.

While the viscometer 20 may be mounted with its member 126 in the liquidreservoir 130, for ink for example, it is shown in FIGURE 12 as mountedwith its member 126 in a sample chamber 131. The ink is delivered fromthe reservoir 130 by means of a pump 132 whose outlet 133 includes avalve controlled, branch line 134 to the sample chamber 131 from which adischarge line 135 effects the return, by gravity flow, to the reservoir130. Solvent is delivered from a suitable source, not shown, through aconduit 136 provided with a normally closed valve 137 adapted to beopened bythe solenoid 133, when energized. Changes in the viscosity ofthe. liquid are immediately sensed by the viscometer 20 land in orderthat the actuation of its flapper valve will effect pneumatically theactuation of the valve 137, there is provided a controller unit,generally indicated at 139, to which air under pressure is deliveredfrom a suitable source through a supply conduit 149 provided with afilter 141 and a pressure regulating valve 142.

In accordance with the invention, it is preferred that not only will thevalve 137 be opened whenever the viscosity of the liquid increasesbeyond a predetermined value and closed when that valve is restored, butalso, should the viscosity not stay within a correctable range thensignals lac-operated. For example, and by means presently to bedetailed, if the ink in reservoir 130 should become exhausted, anaudible signal, the bell 143 and a light source 144, both part of thecontroller unit 139, are

energized, while if the solvent supply fails, then the bell 143 and alight source 145 in the unit 139 are both enerized.

a In accordance with the invention, the flapper valve opens Iwhen thetorque reflects an increase in the viscosity of cometer 20 andprovidedwith a'metering valve 150. A

branch line 151 from the conduit 149 includes a control nozzle 152 and abranch 153 to the control relay 146 thereby to deliver air underpressure, as regulated by the pressure reducing tube 154, against oneface of a diaphragm 155. The stem 155*. of the diaphragm 155 passesfreely through a port 156 in a partition 157 establishing chambers 158and 159. The stem 155 has a valve member 160 in the chamber 153yieldably closing the port 156 under the action of the spring 161 andthe chamber 159 "is vented as at 162. The partition 157 has a passage163 effecting communication between the bore 156 and a conduit 164having a branch 165 to a feedback nozzle 166,

a branch 167 in communication with a bellows unit 168, which effects theoperation of limit and control switches shown in FIGURE 13, and a branchline 169 is in communication with the output pressure indicator 170 ofthe gauge 149.

The feedback nozzle 166 is controlled by a flapper A U-shaped bracket17'? is pivoted as at 178 and it includes, on one side, a depending lug1'79 and an arm 180 provided, at one end, with a pin 181 engageable withthe shaft 172 so that when the arm 189 is tilted, its pin 181 is forceddownwardly, as viewed in FIGURE 11, thereby forcing the bracket 173downwardly and uncovering the control nozzle 152.

Opening of the control nozzle 152 is attended by a decrease in thepressure on the diaphragm 155 so that the valve member 16% moves towardsits closed position thus decreasing the flow of air to the feedbacknozzle 166 enabling the flapper valve 171 to move towards the controlnozzle 152 thus to reestablish equilibrium, but having caused thebellows unit 168 to have moved from a first position into a secondposition in which the control switch is operated until equilibrium isreestablished.

In order that the control, as thus generally described, may respond tothe small pressure drop attendant the opening of the flapper valve, theline 56 is provided with a bellows unit 1812 which moves in response tothe air pressure in the line 56. Such movement of the bellows unit 182is attended by the swinging of an arm 183 connected by a linl; 184 to abell crank lever 185 including a pointer 186. The lever 135 is connectedby a link 187 to a bell crank 18% whose other end is connected by a link189 to the bracket lug 179. By these or equivalent means, slightmovements of the bellows unit 132 are attended by appreciable movementsof the bracket 177. Associated with the pointer 185 is a pivotable index19% moves as by a control knob shaft 191 having a gear 1% meshing with arack 1% arcuate with respect to the pivot 1% of an arm 1% connected by alink 197 to an arm 19-5 fixed to the index 192.

In FIGURE 13, the circuitry is detailed by which the solenoid 138 of thevalve 137 in control of the solvent feed, the bell 14-3, and the lightsources 144 and 145 are appropriately energized or tie-energized bypressure changes in the bellows unit 1&8.

Limit switches 29 i and 292 and a control switch 233 are associated withthe bellows unit. In one position, when the pressure in the bellows unit163 is at a minimum, the contacts 264 and 265 are connected to thecontact 2536. In the other position, when the pressure in the bellowsunit 169 is at a maximum, say lb. p.s.-i., the contacts 2% and 2il5 areconnected to the contact 237 of the switch 281.

In the position of the switch 2532, when the bellows pressure is low,its contacts 208 and 2d; are connected to its contact 21% while, whenthe bellows pressure is high, the contacts 2&8 and 299 are connected tothe contact 211.

The contacts 212 and 213 of the switch 293 are interconnected wheneverthe viscometer senses the demand for solvent and the contact 212 ha alead 214 provided with a normally open switch 215.

A circuit 216 includes a pair of parallel leads 21'? and 218 having thenormally open switches 219 and 22b, respectively, of a relay 221 whichare closed when its coil 222 is energized. The lead 218 includes thesolenoid 138 while the lead 217 includes a normally closed switch 223and is connected to the coil 222 via the lead 224 to which the lead 214is also connected.

The circuit 215 is also provided with a parallel lead 225 which includesa timer motor 226 connected to a cam 227 by an indicated drive 228 whichis operative to close the switch 215 and to open the switch 223 atpredetermined intervals, say once every three seconds. Another parallellead 229 includes the contact 206 of the limit switch 2%, the contact213 of the switch 2%, and the contact 211 of the limit switch 292.

From the foregoing, it will be apparent that whenever the viscometersenses a need for solvent, the bellows unit 168 is immediately operativeto close the control switch 203 thus energizing the relay coil 222 viathe leads 214 and 224 thus to close the relay switches 219 and 220 toenergize the solenoid 138 with the lead 217 being also in circuit withthe lead 224 to function as a holding circuit and the lead 218 closedwith respect to the solenoid 138.

Should the low pressure limit of the bellows unit 168 be reached, thenthe contacts 2%, 205, and 2% of the switch 201 are interconnected as arethe contacts 208, 299, and 2N of the limit switch 262. A lead 236interconnects the leads 204, 205, 2%, and 209, while a lead 231 connectsthe contact 2959 to the alarm bell 143 and a lead 232 connects thecontact 210 and the light source 145 which then visually indicates thatlow viscosity limits are reached indicating, for example, ink failure.

Should the high pressure limit be reached by the bellows unit 167, thecontacts 264, 205, and 297 of the switch 201 are interconnected as arethe contacts 208, 209, and 211 of the limit switch 262. The lead 231 tothe bell 143 is, accordingly, in circuit, and the contact 297 has a lead233 to the light source 144, thus visually to indicate that highviscosity limits prevail indicating, for example, solvent failure.

I claim:

I. In a device for responding to changes in the viscosity of a liquid, adrive shaft, a driven shaft, including a member to be immersed in theliquid to be subjected to the drag thereof, a connection between saidshafts operable to permit limited relative rotation therebetween whenthe driven shaft torque exceeds a predetermined value, a spring one endof which is connected to said driven shaft, and a connection between theother end of said spring and said drive shaft and including an airconduit provided with a valve port carried by said drive shaft, and aport closing member carried by said other spring end and closing saidport until relative shaft movement occurs.

2. In a device for responding to changes in the viscosity of a liquid, adrive shaft, a flywheel resiliently connected to said drive shaft, adriven shaft including a member to be immersed in the liquid to besubjected to the drag thereof, a connection between said shafts operableto permit limited relative rotation therebetween when the driven shafttorque exceeds a predetermined value, a spring one end of which isconnected to said driven shaft, and a connection between the other endof said spring and said drive shaft and including an air conduitprovided with a valve port carried by said drive shaft, and a portclosing member carried by said other spring end and closing said portuntil relative shaft movement occurs.

3. In a device for responding to changes in the viscosity of a liquid, adrive including a drive shaft and a flywheel, an outlet member carriedby said drive and provided with an outlet port, means for delivering airto said member while said drive is in operation, a valve member for saidport movable relative thereto into and out of a port closing position, aspiral spring connected to said valve member, and first and seconddriven members rotatable relative to each other, said first drivenmember being connected to said drive shaft, said second driven memberbeing connected to said spring and including a member to be immersed inthe liquid to be subjected to the drag thereof, said spring normallybeing the driving connection between said drive shaft and said seconddriven member and then holding said valve member in a first position andsaid second driven member rotating relative to said first driven memberand said drive shaft when the torque exceeds a predetermined value to soafiect said spring as to move said valve member into a second position,said first driven member driving said second member on such relative r0-tation to a predetermined extent.

4-. In a device for responding to changes in the viscosity of a liquid,a drive shaft including a flywheel, an outlet member on said flywheelprovided with an outlet port, means for delivering air to said memberwhile said fly wheel is rotating, a valve member for said port movablerelative thereto into and out of a port closing position and including aconnector disposed diametrically with respect to said wheel and having apivot coaxial with said wheel,

a spring connected to the free end of said connector, and first andsecond driven members rotatable relative to each other, said firstdriven member being connected to said drive shaft, said second drivenmember being connected to said spring and including a member to beimmersed in the liquid to be subjected to the drag thereof, said springnormally being the driving connection between said drive shaft and saidsecond driven member and then holding said valve member in a firstposition and said second driven member rotating relative to said firstdriven member and said drive shaft when the torque exceeds apredetermined value to so afliect said spring as to move said valvemember into a second position, said first driven member driving saidsecond driven member on such rotation to a predetermined extent.

5. In a device for responding to changes in the viscosity of a liquid, adrive shaft including a flywheel, an outlet member on said flywheelhaving an outlet port, means for delivering air to said member whilesaid flywheel is rotating, a valve member for said port movable relativethereto into and out of a port closing position, a spring connected tosaid valve member, and first and second driven members rotatablerelative to each other, said first driven member including a tubularportion and said second driven member including a portion extendingtherethrough, said first driven member being connected to said springand including a member to be immersed in the liquid to be subjected tothe drag thereof, said spring normally being the driving connectionbetween said drive shaft and said second driven member and then holdingsaid valve member in a first position and" second driven member rotatingrelative to said first driven member and said drive shaft when thetorque exceeds a predetermined value to so affect said spring as to movesaid valve member into a second position, said first and second drivenmembers also including portions interengaging on such rotation to apredetermined extent and said first driven member driving said seconddriven member on such interengagement.

6. In a device for responding to changes in the viscosity of a liquid, adrive' shaft including a flywheel, an outlet member on said flywheelprovided with an outlet port, means for delivering air to said memberwhile said flywheel is rotating, a valve member for said 'port movablerelative thereto into and out of a port closing position, a

spring connected to said valve member, a support and first and seconddriven members rotatable relative to each other, said first drivenmember including a tubular portion journalled on said support and saidsecond driven member including a portion extending freely through saidtubular portion, said first driven member being connected to said driveshaft, said second driven member being connected to said spring andincluding a member to be immersed in the liquid to be subjected to thedrag thereof, said spring normally being the driving connection betweensaid drive shaft and said second driven member and then holding saidvalve member in a first position and said 'second driven member rotatingrelative to said first driven member and to said drive shaft when thetorque exceeds a predetermined value to so affect said spring as to movesaid valve member into a second position, each of'said driven membersincluding a U-shaped portion, each pro- 7 viding an upper and a lowerarm interconnected at their outer ends, the upper arm of the portion ofthe second driven member being at the lower end thereof, and the lowerarm of the first driven member being disposed between the arms of saidsecond driven member and including a bearing rotatably supporting thelower end ofsaid second driven member; said portions interengaging onrotation of said second driven member relative to said first drivenmember to a predetermined extentand thereafter being driven thereby.

7. The device of claim 6 in which the bearing of the U-shaped portion ofthe first driven member has a resilient connection with the lower armthereof.

8. In a device for responding to changes in the viscosity of a'liquid, adrive shaft including a flywheel, an outlet member of said flywheelprovided with an outlet port, means for delivering air to said memberwhile said fly wheel is rotating, a valve member for said port movablerelative thereto into and out of a port closing position, a springconnected to said valve member, a support and first and second drivenmembers rotatable relative to each other, said first driven memberincluding a tubular portion journalled on said support and said seconddriven member including a portion extending freely through said tubularportion, said first driven member being connected to said drive shaft,said second driven member being connected to said spring, said springnormally being the driving connection between said drive shaft and saidsecond driven member and then holding said valve member in a firstposition and said second driven member rotating relative to said firstdriven member and to said drive shaft when the torque exceeds apredetermined value to so affect said spring as to move said valvemember into a second position, each of said driven members including aU-shaped portion, each providing an upper and a lower arm interconnectedat their outer ends, the upper arm of the portion of the second drivenmember being at the joint connecting said driven shaft to the lower armof the U-shaped portion of the second driven member.

9. The device of claim 8 in which the lower arm of the U-shaped portionof the second driven member has a resilient support for the universaljoint.

10. In a device for responding to changes in the viscosity of a liquid,a drive shaft including a flywheel having openings and provided withspindle ends, an outlet member on said flywheel provided with an outletport, means for delivering air to said member while said flywheel isrotating, a valve member for said port movable relative thereto into andout of a port closing position, a spring connected to said valve member,and first and second driven members rotatable relative to each other, aU- shaped member providing upper and lower arms interconnected at theirouter ends through an opening in the flywheel, the upper arm beingconnected to said drive shaft, said first driven member being connectedto the lower arm of said U-shaped member, said spindle ends beingrotatably supported by the arms of said U-shaped member, said seconddriven member being connected tov said spring and including a member tobe immersed in the liquid to be subjected to the drag thereof, saidspring normally being the driving connection between said drive shaftand said second driven member and then holding said valve member in afirst position and said second driven'member rotating relative to saidfirst driven member and to said drive shaft when the torque exceeds apredetermined value to so affect said spring as'to move said valvemember into a second position. i

11'. In a device for respondingto changes in the viscosity of a liquid,a drive shaft including a flywheel having openings and provided withspindle ends, an outlet member on said flywheel provided with an outletport, means opening, said valve member being connected to the outer endof said upper arm, said connector arms being disposed diametrically withrespect to said flywheel, a spring connected to the outer end of saidlower connector arm, and first and second driven members rotatablerelative to each other, a U-shaped member providing upper and lower armsinterconnected at their outer ends through an opening in the flywheel,the upper being connected to said drive shaft, said first driven memberbeing connected to the lower arm of said U-shaped member, said spindleends being rotatably supported by the arms of said U- shaped member,said second driven member being connected to said spring and including amember to be immersed in the liquid to be subjected to the drag thereof,said spring normally being the driving connection between said driveshaft and said second driven member and then holding said valve memberin a first position and said second driven member rotating relative tosaid first driven member and to said drive shaft when the torque exceedsa predetermined value to so affect said spring as to move said valvemember into a second position.

12. In a device for responding to changes in the viscosity of a liquid,a hollow drive shaft including a flywheel, an outlet member on saidflywheel provided with an outlet port and in communication with theinterior of said shaft, means for delivering air into the upper end ofsaid shaft while it is rotating, a valve member for said port movablerelative thereto into and out of a port closing position, a springconnected to said valve member, and first and second driven membersrotatable relative to each other, said first driven mem er connected tosaid drive shaft, said second driven member being connected to saidspring and including a member to be immersed in the liquid to besubjected to the drag thereof, said spring normally being the drivingconnection between said drive shaft and said second driven member andthen holding said valve member in a first position and said seconddriven member rotating relative to said first driven member when thetorque exceeds a predetermined value to so atfect said spring as to movesaid valve member into a second position, said driven memberinterengaging on such rotation to a predetermined extent and then saidfirst driven member driving said second driven member.

13. The device of claim 12 in which the means for delivering air intothe hollow shaft comprises an air supply conduit including a nozzlerotatably entrant of the upper end of the shaft, and a resilient memberyieldably holds the nozzle seated.

14. In a device for responding to changes in the viscosity of a liquid,a drive shaft including a flywheel having an opening, an outlet memberon said flywheel provided with an outlet port, means for delivering airto said member while said flywheel is rotating, a connection disposeddiametrically with respect to said wheel and pivoted coaxially butpivoting inde endntly thereof, a valve member for said port movablerelative thereto into and out of a port closing position and connectedto one end of said connector, a spring connected to the other end ofsaid connector, and adjustable resilient means carried by said wheel andyieldably opposing movement of said connector, and first and seconddriven members rotatable relative to each other, said first drivenmember being connected to said drive shaft, said second driven memberbeing connected to said spring and including a member to be immersed inthe liquid to be subjected to the drag thereof, said spring normallybeing the driving connection between said drive shaft and said seconddriven member and then holding said valve member in a first position,said second driven member rotating relative to said first driven memberwhen the torque exceeds a predetermined value to so affect said springas to move said valve member into a second position, said driven membersinterengaging on such rotation to a predetermined extent and then saidfirst driven men ber driving said second driven member.

Cir

15. In a device for responding to changes in the viscosity of a liquid,a drive shaft, a flywheel, a resilient and yieldable driving connectionbetween said shaft and said flywheel, an outlet member on said flywheelprovided with an outlet port, means for delivering air to said memberwhile said flywheel is rotating, a valve member for said port movablerelative thereto into and out of a port closing position, a drive shaft,a spring connected to said valve member, and first and second drivenmembers rotatable relative to each other, said first driven member beingcon nected to said drive shaft, said second driven member beingconnected to said spring and including a member to be immersed in theliquid to be subjected to the drag thereof, said spring normally beingthe driving connection between said drive shaft and said second drivenmember and then holding said valve member in a first position, saidsecond driven member rotating relative to said first driven member whenthe torque exceeds a predetermined value to so affect said spring as tomove said valve member into a second position, said driven membersinferengaging on such rotation to a predetermined extent and then saidfirst driven member driving said second driven member.

16. In a device for responding to changes in the viscosity of a liquid,a drive shaft, a flywheel, an outlet member on said flywheel providedwith an outlet port, and being adjustable towards or away from the rimof said wheel, means for delivering air to said member While saidflywheel is rotating, a valve member for said port movable relativethereto into and out of a port closing position, a drive shaft, a springconnected to said valve member, and first and second driven membersrotatable relative to each other, said first driven member beingconnected to said drive shaft, said second driven member being connectedto said spring and including a member to be immersed in the liquid to besubjected to the drag thereof, said spring normally being the drivingconnection between said drive shaft and said second driven member andthen holding said valve member in a first position, said second drivenmember rotating relative to said first driven member when the torqueexceeds a predetermined value to so affect said spring as to move saidvalve member into a second position, said driven members interengagingon such rotation to a predetermined extent and then said first drivenmember driving said second driven member.

17. In a device for responding to changes in the viscosity of a liquid,a drive shaft, a driven shaft axially alined therewith but spacedtherefrom and including a member to be immersed in the liquid to besubjected to the drag thereof, a connection between said shafts operableto permit limited relative rotation therebetween when the driven shafttorque exceeds a predetermined value, a spring one end of which isconnected to said driven shaft, and a connection between the other endof said spring and said drive shaft and including an air conduitprovided with a valve port carried by said drive shaft,- and a portclosing member carried by said other spring end and closing said portuntil relative shaft movement occurs, said port closing member beingbetween the proximate ends of said shafts and pivotally supportedthereby.

18. In a device for responding to changes in the viscosity of a liquid,a drive shaft axially aligned therewith but spaced therefrom, a flywheelpivotally supported by said shaft and resiliently connected thereto, adriven shaft including a member to be immersed in the liquid to besubjected to the drag thereof, a connection between said shafts operableto permit limited relative rotation thercbetween when the driven shafttorque exceeds a. predetermined value, a spring one end of which isconnected to said driven shaft, and a connection between the other endof said spring including an air conduit provided with a valve portcarried by said flywheel, and a port closing member carried by saidother spring end and closing said port until relative shaft movementoccurs, said port closr it shafts and 'pivotally supported thereby, bothconnections being independent of said flywheel during said relativeshaft movement. I p 19. In a device for responding to changes in-theviscosity of a liquid, a drive shaft a driven shaft including a memberto be immersed in the liquid to be subject to the drag thereof, aconnection betwen said shafts operable to permit relative rotationtherebetween when the driven shaft torque exceeds a predetermined value,a spring, one

end of said spring being connected to said driven shaft, a connectionbetween the other end of said spring and said drive shaft and includinga conduit provided with a valve port carried by said drive shaft, and aport closing member carried by said other spring end and controllingsaid 12 port until relative movement between the shafts occurs, apressure-operated unit, a supply of fluid under a predetermined pressureincluding a pair of conduits, one in communication with said unit andthe other in communication with said valve port, and a throttling deviceinterposed between said supply and said conduits, said unit operatingthroughout the range of pressure in said conduits as determined by saidport closing member.

References Cited in'the file of this patent V UNITED STATES PATENTS2,679,750 Brookfield June 1, 1954 2,772,605 Schlapak Dec. 4, 19562,917,065 Monk Dec. 15, 1959

1. IN A DEVICE FOR RESPONDING TO CHANGES IN THE VISCOSITY OF A LIQUID, ADRIVE SHAFT, A DRIVEN SHAFT, INCLUDING A MEMBER TO BE IMMERSED IN THELIQUID TO BE SUBJECTED TO THE DRAG THEREOF, A CONNECTION BETWEEN SAIDSHAFTS OPERABLE TO PERMIT LIMITED RELATIVE ROTATION THEREBETWEEN WHENTHE DRIVEN SHAFT TORQUE EXCEEDS A PREDETERMINED VALUE, A SPRING ONE ENDOF WHCIH IS CONNECTED TO SAID DRIVEN SHAFT, AND A CONNECTION BETWEEN THEOTHER END OF SAID SPRING AND SAID DRIVE SHAFT AND INCLUDING AN AIRCONDUIT PROVIDED WITH A VALVE PORT CARRIED BY SAID DRIVE SHAFT, AND APORT CLOSING MEMBER CARRIED BY SAID OTHER SPRING END AND CLOSING SAIDPORT UNTIL RELATIVE SHAFT MOVEMENT OCCURS.